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Deuterium-depleted water (DDW), also known more ambiguously as light water, is water which has a lower concentration of deuterium than occurs naturally. Deuterium a heavier isotope of hydrogen which has, in addition to its one proton, a neutron, that roughly doubles the mass of the hydrogen atom. In Vienna Standard Mean Ocean Water, deuterium occurs at a rate of 155.76 ppm. The production of heavy water involves isolating and removing deuterium within water. The by-product of this process is light water. Production of light water can result during electrolysis, distillation, and desalination. Filtration through special membranes and crystallization are also considered preparation methods. It can also be produced directly using the Girdler sulfide process.〔 Experiments have shown that consumption of light water may be beneficial as an adjunct to chemotherapy. A 1999 Romanian study found that water with only 30 ppm deuterium produced marked improvement in survival rates of mice bombarded with ionizing radiation. A study of four patients with brain metastases from lung cancer found a three-month regimen of light water "noticeably prolonged" their survival time. A 2010 Hungarian study found significant improvement in the survival times of prostate cancer patients treated with light water. Despite Gilbert Lewis' call in 1934 for such experiments., research on the effects of deuterium-depletion on living cells has been very limited with less than a dozen peer-reviewed research papers available via PubMed in mid-2011 Depleted water (125 ppm deuterium corresponds to the deuterium:protium ratio D:H=1:7695) at a consumption as high as 2 litres per day can influence the deuterium concentration in human body (average 40 litres with deuterium:protium ratio about D:H = 1:6418) for less than 1% (decreasing the normal ratio to D:H = 1:6472). A 1963 American paper is reported to infer that no biological effect should be expected at this level,〔Thompson, J.F.: Biological effects of deuterium, Pergamon Press, New York 1963.〕 though new researches are currently carried on in eastern Europe. Qlarivia is a bottled water brand made in Romania, that boasts as having the lowest deuterium content of the market, that of 25 parts per million. ==See also== * Kinetic isotope effect * Light water (disambiguation) * Properties of water 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Deuterium-depleted water」の詳細全文を読む スポンサード リンク
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